Brazil, US Identify Molecule to Help Fight Citrus Greening Disease

Researchers have identified the molecule that attracts the insect that transmits citrus greening disease, a development expected to help farmers control a plague that has destroyed trees in growing regions of Brazil and the United States.

The scientific breakthrough, shared with Reuters exclusively on Tuesday, is the result of six years of research on Diaphorina citri, the vector of citrus greening disease.

The molecule was discovered by Fundo de Defesa da Citricultura (Fundecitrus), a research center sponsored by farmers and orange juice producers in Brazil, in partnership with the University of California, Davis and the University of Sao Paulo's Agricultural College, known as Esalq.

The next step will be to synthesize the pheromone from the molecule and create a product that will work as a kind of trap to attract and neutralize the insect. Then scientists hope to reduce the spread of a disease that resulted, since 2005, in the destruction of almost half of Brazil's current orange tree area.

"This will not cure greening disease, but it will allow us to work in an intelligent and assertive way against the insect," Juliano Ayres, general manager at Fundecitrus, said in a telephone interview.

The first commercial solution should be available to farmers in a year, said Walter Leal, the Brazilian researcher representing UC Davis who participated in the interview.

Based on government data, Brazil's main producing regions of Sao Paulo and Minas Gerais have almost 175 million trees planted on around 415,000 hectare (1.025m acres), Fundecitrus said.

Around 32 million trees are infected, the data show.

Citrus greening, or Candidatus Liberibacter asiaticus, is incurable and one of the most serious citrus plant diseases in the world, according to the United States Department of Agriculture.

The infected trees produce fruits that are green, misshapen and bitter, unsuitable for sale as fresh fruit or for juice.